British government in dark over who behind health service cyber attack

The national railway system said that although it was attacked, rail network operations were unaffected.

NHS Borders is among more than 30 United Kingdom health boards being targeted by cyber attacks.

Colchester General Hospital has been affected by the NHS cyber hack. "Our patients are being very understanding so far".

Anyone seeking non-urgent medical assistance is advised to call NHS 111 for free advice, or to visit their local pharmacy. Please do not attend A&E unless it's an emergency.

What's caused the attack?

An increase in activity of the malware was noticed starting from 8am CET (07:00 GMT) Friday, security software company Avast reported, adding that it "quickly escalated into a massive spreading".

The cyber attack, which struck on Friday afternoon, has so far infected tens of thousands of computers in almost 100 countries, including NHS hospitals in the UK.

"When people ask what keeps you up at night, it's this", said Chris Camacho, chief strategy officer at Flashpoint, a NY security firm tracking the attacks.

Patients of the state-funded country-wide service are facing days of chaos as appointments and surgeries were cancelled after almost 45 NHS organisations from London to Scotland were hit in the "ransomware" attack on Friday.

Pictures posted on social media showed screens of NHS computers with images demanding payment of 300 U.S. dollars worth of the online currency Bitcoin, saying: "Ooops, your files have been encrypted!"

Hospitals across the country have been hit by a "ransomware" attack that froze computers, shutting wards, closing emergency rooms and bringing treatment to a halt.

The cyber attack that crippled systems worldwide on Friday affected around around 99 countries, including India, according to reports in the media.

As similar widespread ransomware attacks were reported in Spain, Romania and elsewhere, experts warned that online extortion attempts by hackers are a growing menace.

"I would like to thank all of the NHS staff who are continuing to work hard to ensure that the impact of this attack is kept to an absolute minimum".

"We are taking the highly unusual step of providing a security update for all customers to protect Windows platforms that are in custom support only, including Windows XP, Windows 8, and Windows Server 2003".

Doctors at some surgeries were forced to use pen and paper to record patient details following the attack. IT plays such a huge role in modern healthcare at looking at past notes. "As a result, we've got this terrible situation". In 2014 when Windows stopped supporting, the NHS played £5m to have an extra year's support. "We and all of the other Royal Colleges have been calling for serious infrastructure investment for a long time". It initially said 16 NHS organizations had reported being hit, and more reports came in as the day went on.

Home Secretary Amber Rudd admitted files may have been lost, telling BBC Breakfast: "We will find out over the next few days if there are any holes in [the backing-up of files]".

Microsoft on Friday said it was pushing out automatic Windows updates to defend clients from WannaCry.

"I don't think it's to do with that preparedness".

Ms Rudd will chair a Cobra meeting in Whitehall today (Saturday) at 2.30pm.

A statement from Provide Community Interest Company, which runs community health services in mid-Essex, said: "Provide Community Interest Company delivers community health services in mid Essex and some of its IT systems have been affected by the NHS cyber-attack".